carbon filter?

I changed my pollen filter today. on the way to work i popped into local motor factors collected the only pollen listed for my model and year. upon finally getting the old filter out discovered they were different. so went back to motor factors and was informed that the one i had took out was a carbon filter!!! . so i had to adapt the the new paper filter slightly to fit. has anyone else come across this and if so what is the purpose of a carbon filter? am i losing out by not using one?

carbon pollen filters are supposed to be more efficient in filtering than paper filters, i run my car without the pollen filter as when i was last servicing the car the motor factors didn't have a pollen filter in stock and my heater on full blast could be compared to a slight breeze